Saved Bookmarks
| 1. |
Let `A and B` be two distinct points on the parabola `y^2 = 4x`. If the axis of the parabola touches a circle of radius `r` having `AB` as its diameter, then the slope of the line joining `A and B` can be (A) `- 1/r` (B) `1/r` (C) `2/r` (D) `- 2/r`A. `+-1/r`B. `+-2/r`C. `+-3/r`D. `+-1/2r` |
|
Answer» Correct Answer - B Let `A(t_(1)^(2), 2t_(1))" and "B(t_(2)^(2), 2t_(2))` be two point on `y^(2)=4x`. The coordinates of the cetre of the circle are `((t_(1)^(2)+t_(2)^(2))/2,t_(1)+t_(2))` Since the circle with diameter AB touches the axis of the parabola and is of radius r. `:. "t_(1)+t_(2)=+r` `:." Slope of AB"2/(t_(2)+t_(1))=+-2/r` |
|